Clathrin- and dynamin-dependent endocytic pathway regulates muramyl dipeptide internalization and NOD2 activation

Noemí Marina-García, Luigi Franchi, Yun Gi Kim, Yonjun Hu, David E. Smith, Geert Jan Boons, Gabriel Núñez

Research output: Contribution to journalArticle

96 Citations (Scopus)

Abstract

Muramyl dipeptide (MDP), the NOD2 agonist, induces NF-κB and MAPK activation leading to the production of antimicrobial and proinflammatory molecules. MDP is internalized into acidified vesicles in macrophages. However, the endocytic mechanism of MDP uptake that induces NOD2 signaling is unknown. We now report the identification of an endocytosis pathway dependent on clathrin and dynamin that mediates MDP internalization and NOD2 activation. Intracellular MDP uptake was inhibited by chlorpromazine, a drug that disrupts clathrin-dependent endocytosis, but not by compounds that block pinocytosis or cellular entry via scavenger or mannose receptors. In contrast, MDP uptake and NOD2-dependent signaling were unimpaired in macrophages deficient in PepT1, a peptide transporter previously implicated in MDP internalization. Both chlorpromazine and knockdown of clathrin expression by RNA interference attenuated MDP-induced NF-κB and MAPK activation. Furthermore, MDP uptake and NOD2-dependent signaling were impaired by inhibition of dynamin, a GTPase required for budding of clathrin-coated vesicles from the plasma membrane. Finally, bafilomycin A, a specific inhibitor of the vacuolar proton pump, blocked MDP accumulation in acidified vesicles and cytokine responses, suggesting that vacuolar maturation is important for MDP-induced NOD2 signaling. These studies provide evidence for a clathrin- and dynamin-dependent endocytosis pathway that mediates MDP uptake and NOD2 activation.

Original languageEnglish
Pages (from-to)4321-4327
Number of pages7
JournalJournal of Immunology
Volume182
Issue number7
DOIs
Publication statusPublished - 2009 Apr 1

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

Fingerprint Dive into the research topics of 'Clathrin- and dynamin-dependent endocytic pathway regulates muramyl dipeptide internalization and NOD2 activation'. Together they form a unique fingerprint.

  • Cite this